Silverlight文件下载完美版

页面：hlink.NavigateUri = new Uri(serviceHelper.baseUrl + servicePath.DownFilePath + "?filename="+((Sys_AttachmentLibrarymodel)selDownFile.SELEctedItem).FileUrl.ToString());

服务端：DownLoadFileHandler.ashx

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.IO;

public class DownLoadFileHandler : Baseservice
{

    public override void Processrequest(httpContext context)
    {
        Context = context;
        Result = new ActionResult();

        String filename = context.request.QueryString["filename"]; //客户端保存的文件名 
        filename = httpUtility.UrlDecode(fileName);
        String filePath = ConfigHelper.UploadPath+ filename; //路径 
        FileInfo fileInfo = new FileInfo(filePath);
        if (fileInfo.Exists)
        {
            byte[] buffer = new byte[102400];
            context.Response.Clear();
            FileStream iStream = File.openRead(filePath);
            long dataLengthToRead = iStream.Length; //获取下载的文件总大小 
            context.Response.ContentType = "application/octet-stream";
            context.response.addheader("Content-Disposition","attachment;  filename=" +
                               httpUtility.UrlEncode(filename.SubString(filename.LasTindexOf("\\")+1),System.Text.Encoding.UTF8));
            while (dataLengthToRead > 0 && context.Response.IsClientConnected)
            {
                int lengthRead = iStream.Read(buffer,Convert.ToInt32(102400));//'读取的大小 
                context.Response.outputStream.Write(buffer,lengthRead);
                context.Response.Flush();
                dataLengthToRead = dataLengthToRead - lengthRead;
            }
            context.Response.Close();
            context.Response.End();
        } 

        // 输出结果
        OutputResult();
    }

}